Stock-Based Compensation (Options and Common Shares Reserved for Grant) (Details) - Stock Options $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended
	Mar. 31, 2020 USD ($) $ / shares shares
Options Outstanding [Roll Forward]
Options Outstanding, Beginning Balance (in shares) | shares	3,348
Options Outstanding, Granted (in shares) | shares	704
Options Outstanding, Exercised (in shares) | shares	(462)
Options Outstanding, Forfeited / Canceled (in shares) | shares	(61)
Options Outstanding, Ending Balance (in shares) | shares	3,529
Options Outstanding, Exercisable (in shares) | shares	2,053
Weighted Average Exercise Price [Roll Forward]
Weighted Average Exercise Price, Beginning Balance	$ 10.85
Weighted Average Exercise Price, Granted	17.12
Weighted Average Exercise Price, Exercised	10.23
Weighted Average Exercise Price, Forfeited / Canceled	11.48
Weighted Average Exercise Price, Ending Balance	12.17
Weighted Average Exercise Price, Exercisable	$ 10.65
Weighted Average Remaining Contractual Term [Abstract]
Weighted Average Remaining Contractual Term, Outstanding	4 years 3 months 18 days
Weighted Average Remaining Contractual Term, Exercisable	3 years 2 months 12 days
Aggregate Intrinsic Value, Outstanding | $	$ 689	[1]
Aggregate Intrinsic Value, Exercisable | $	$ 689	[1]
Closing Stock Price	$ 9.54

[1] The aggregate intrinsic value represents the total pre-tax intrinsic value, based on our closing stock price of $9.54 as of March 31, 2020, which would have been received by the option holders had all option holders exercised their options as of that date. The intrinsic value of an option is the amount by which the fair value of the underlying stock exceeds its exercise price.